REVIEWS 301 
The Gaspé peninsula is the northeastern extremity of the Appalachian 
mountain system, and the geologic structure consists of a series of parallel 
folds similar to those so well known farther to the southwest, and formed 
by the same great earth disturbances. The Devonian rocks with whose 
faunas the memoir is concerned lie unconformably upon older Paleozoic 
formations. ‘They include the Gaspé limestones and sandstones of Logan. 
The Gaspé limestone attains a thickness of 2,oro feet and is frequently 
highly fossiliferous. Three divisions are recognized, the St. Alban lime- 
stone below, followed by the Bon Ami limestone, and this again followed 
by the Grand Greve limestone. The Gaspé sandstones, according to 
Logan’s estimates, attain the enormous thickness of 7,000 feet, but this 
estimate may be too large by reason of the repetition of some beds by 
faulting. 
From the St. Alban beds a fauna of 51 species is described ‘‘of which 
fully one-half occur in the typical Helderbergian faunas (Coeymans and 
New Scotland) to the southwest.”’ The fauna of the Bon Ami limestone 
is small and of much less importance, but the Grand Greve limestone has 
furnished a fauna of about 150 recorded species. This fauna 
has a less proportion of community of species with the Helderbergian but still a 
substantial number of species (21 identities and 14 close affines). With the 
Oriskany there is a larger community of species (39 identities and 13 affines) 
and so commanding is this percentage and the composition of the congeries itself, 
consisting as it does of the most typical species of the Oriskany, that it compels 
this inference: The development of the Oriskany fauna was synchronous with 
the prevalence of the Helderbergian fauna in this region and the differentiation 
of the two faunal elements, which we commonly recognize in the Appalachian 
regions as Helderberg and Oriskany, was subsequent in date to the development 
of the combined faunas together in Gaspé. Thus again we have evidence that 
the Gaspé basin was a center of dispersion of these two faunas and that the 
direction of this dispersion so far as the facts now indicate was still toward the 
southwest. 
The marine fauna of the enormously thick Gaspé sandstone is of but 
limited extent, and occurs in a comparatively thin horizon of calcareous 
sandstones which probably lies near the base of the entire series. This 
great accumulation of arenaceous sediment seems to have been deposited © 
in a great costal lagoon into which terrigenous sediments were rapidly 
swept. The stratum of marine sediments probably represents overwash 
of the outside waters in time of stress, bringing in the marine organisms 
which are now found as fossils. Only about fifty species are recorded in 
this fauna of which ‘‘one-seventh to one-sixth are survivors of the Oriskany 
element in the Grand Gréve limestones. With the Hamilton faunas from 
